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Biomedical subjects

Y C Chan

Publications and source records attributed to Y C Chan.

At least 19 recordsLinked to original sources
PubMed2006

Confirmatory factor analysis of the Child Abuse Potential Inventory: results based on a sample of Chinese mothers in Hong Kong.

OBJECTIVES: To evaluate whether or not the original six-factor structure of the Child Abuse Potential (CAP) Inventory suggested by [Milner, J.S. (1986). The Child Abuse Potential Inventory: Manual (2nd ed.). DeKalb, IL: Psytec. Inc.] can be confirmed with data from a group of Chinese mothers in Hong Kong. METHOD: Eight hundred and ninety-seven mothers from 13 child care centers in Hong Kong successfully completed a set of structured questionnaires consisting, among others, of the 77-item Abuse Scale of the CAP Inventory. A confirmatory factor analysis (CFA) was performed to determine whether the data fits the factorial structure of the CAP Inventory identified by Milner (1986). RESULTS: The root mean square error of approximation (RMSEA) of the model epsilona) is 0.031, indicating a close fit of the model in relation to the degrees of freedom. On testing the close fit against the null hypothesis that Ho: epsilona<or=0.05, the associated p-value is almost one. This suggests that the probability that Ho is true is extremely high. The estimated expected value of the cross-validation index (ECVI) is 6.185, which is less than the ECVIsat (6.703), giving another indication on the fitness of the model. Other fit indices also provide support for the model fitness. CONCLUSION: The original six-factor structure of the CAP Inventory tested by CFA is acceptable. The theoretical constructs underlying the CAP Inventory are supported by data collected from Chinese mothers in Hong Kong.

Adult↗
PubMed2006

AT1 receptor antagonism ameliorates acute pancreatitis-associated pulmonary injury.

Acute pancreatitis (AP) is an inflammatory disease characterized by tissue edema, necrosis and hemorrhage. The mortality rate associated with this disease is particularly high when the inflammation has become systemic. Recently, activation of the pancreatic renin-angiotensin system (RAS) was shown to play a role in AP. The present study investigated whether administering an AT1 receptor antagonist decreases the severity of AP and pancreatitis-induced systemic inflammation, particularly pulmonary injury. Rats with AP-associated lung injury were induced by multiple doses of caerulein, which was demonstrated in the previous studies. Three injections of losartan (200 microg/ kg/h) were given 30 min prior to the first injection of caerulein. The results demonstrated that caerulein injections resulted in significant increases in pancreatic and pulmonary myeloperoxidase (MPO) activities, and losartan treatment attenuates these effects. Lung microvascular permeability was also significantly improved by losartan treatment. Losartan prevented caerulein-induced pancreatic and pulmonary morphological alterations, but not elevations in serum alpha-amylase or pancreas/body weight ratio. These data indicate that losartan treatment can attenuate pancreatic and lung injury. Thus, the implication is that a blockade of AT1 receptors may have a clinical application for the treatment of AP and, perhaps more importantly, subsequent pulmonary complications.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2006

Bickerstaff's brainstem encephalitis: can it recur?

Bickerstaff's brain-stem encephalitis is usually a monophasic post-viral inflammatory illness characterized by progressive ophthalmoplegia, ataxia and disturbance of consciousness (or hyper-reflexia). Since the clinical spectrum of Bickerstaff encephalitis may overlap with the Miller-Fisher and Guillain-Barré syndromes, the presence of anti- GQ1b antibodies and abnormal brain MRI can help to support its diagnosis. However, absence of anti-GQ1b antibodies and normal MRI do not exclude the diagnosis, which remains based on clinical criteria and exclusion of other etiologies. We report a case of recurrent Bickerstaff's brainstem encephalitis with no identifiable antecedent illness, and overlapping features of Miller Fisher and Guillain-Barré syndromes, in the presence of negative anti-GQ1b antibodies and repeatedly normal MRI of the brain.

Brain Stem↗
PubMed2006

Aconite poisoning in camouflage.

The Toxicology Reference Laboratory has confirmed 10 cases of aconite poisoning from March 2004 to May 2006. In four of these 10 cases, the aconite herb was not listed in the written prescription. We report these four cases to highlight the problem of 'hidden' aconite poisoning.

Aconitum↗
PubMed2005

The use of transcranial magnetic stimulation in the clinical evaluation of suspected myelopathy.

Central motor conduction time (CMCT) and motor evoked potential (MEP) latencies measured by using transcranial magnetic stimulation (TMS) are parameters used to evaluate electrophysiologic function of the corticospinal motor tract. We present 5 cases to illustrate how the use of TMS had contributed to clinical management. CMCT and MEP latency measurements were found to be useful in determining the significance of lesions seen on neuroimaging and helped clinical decisions in the presence of multiple lesions or multiple clinical conditions that cause similar clinical manifestations. TMS study is particularly useful in localizing levels of conduction defect.

Aged↗
PubMed2005

Guidelines of care for cutaneous haemangiomas.

INTRODUCTION: Haemangiomas are common benign tumours of the vascular endothelium. They are extremely heterogenous clinically, with size, location and rate of proliferation having a significant effect on the risk of complications. MATERIALS AND METHODS: The available evidence in the literature was evaluated using the grading system currently employed by the Ministry of Health, Singapore. RESULTS: An uncomplicated haemangioma can be observed for spontaneous involution. However, some haemangiomas may be life- or function-threatening, or have associated structural anomalies. Corticosteroids may be used topically, intralesionally or systematically. Interferon alpha, vincristine and cyclophosphamide are therapeutic options for complicated haemangiomas which do not respond to corticosteroids. Vascular-specific pulse dye laser therapy may be considered for superficial haemangiomas, ulcerated haemangiomas or post-involution sequelae like telangiectasia. The mainstay of therapy for ulcerated haemangiomas is good local wound care, analgesics and treatment of secondary infection. A periorbital haemangioma that obstructs the visual axis or exerts pressure on the globe is an ocular emergency. Systemic corticosteroids and patching of the unaffected eye should be considered. CONCLUSIONS: Medical practitioners should be aware of available therapeutic options for life- or function-threatening haemangiomas. Treatment must be individualised and referral to the relevant specialist should be considered in patients with complicated haemangiomas.

Combined Modality Therapy↗
PubMed2005

Use of ligase chain reaction in early diagnosis of tuberculous meningitis.

INTRODUCTION: Nucleic acid-based amplification tests are currently licensed only for the detection of Mycobacterium tuberculosis in pulmonary specimens. There are insufficient data for extrapulmonary specimens. The aim of this study is to investigate the diagnostic value of these investigations in tuberculous meningitis. MATERIALS AND METHODS: We performed a prospective study using a commercial ligase chain reaction DNA amplification technique [Ligase chain result (LCx) M. tuberculosis; Abbott Laboratories, Abbott Park, IL, USA] on cerebrospinal fluid (CSF) to diagnose tuberculous meningitis and compared the results with standard microbiological data. Conflicting cases were resolved according to the final clinical diagnosis. A total of 54 CSF specimens from 54 patients were tested. RESULTS: Six (11.1%) specimens were culture-positive for M. tuberculosis; of these, only 1 (1.9%) was smear-positive. The sensitivity, specificity, positive predictive value and negative predictive value of the LCx assay, compared with culture results, were 66.7%, 100%, 100% and 96%, respectively. After resolution according to clinical data, the sensitivity, specificity, positive predictive value and negative predictive value were 33.3%, 100%, 100% and 75%, respectively. All controls had negative LCx results. There were no false positives. CONCLUSION: LCx assay is highly specific and complements conventional laboratory diagnostic methods (CSF smear and culture) in the diagnosis of tuberculous meningitis. In the appropriate clinical context, a positive result is strongly suggestive of tuberculosis and could enable antituberculous treatment to be started immediately.

Humans↗
PubMed2005

MBR/RO/ozone processes for TFT-LCD industrial wastewater treatment and recycling.

This research is mainly to explore the treatment capacity for TFT-LCD industrial wastewater recycling by the processes combined with membrane bioreactor (MBR), reverse osmosis (RO) and ozone(O3). The organic wastewater from the TFT-LCD industry was selected as the target. MBR, RO and ozone plants were established for evaluation. An MBR plant consisted of a 2-stage anoxic/aerobic bioreactor and an immersed UF membrane unit was employed. The effluent of MBR was conducted into the RO system then into the ozone system. The RO system consisted of a spiral membrane in the vessel. One bubble column, 75 cm high and diameter 5 cm, were used as the ozonation reactor. On the bottom of ozonation reactor is a porous diffuser for releasing gas, with an aperture of 100 microm (0.1 cm). Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 98.5%. For the TOC item, the average removal efficiency was 97.4%. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of an immersed UF membrane device incorporated with the biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After the treatment of RO, excellent water quality was found. The water quality of permeate was under 5 mg/I, 2 mg/l and 50 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled and reused for the cooling tower make-up water or other purposes. After the treatment of ozone, the treated water quality was under 5 mg/l and 0.852 mg/l for COD and TOC respectively. The test results of MBR, MBR/RO and MBR/RO/ozone processes were compared as possible appropriate treatment technologies applied in TFT-LCD industrial wastewater reuse and recycling.

Bioreactors↗
PubMed2004

The relaxant effect of urocortin in rat pulmonary arteries.

Urocortin is a potent vasodilator, which plays physiological or pathophysiological roles in systemic circulation. However, little is known about its action on pulmonary circulation. The present study was aimed to characterize some cellular mechanisms underlying the relaxant effect of urocortin in isolated rat pulmonary arteries. Changes in isometric tension were measured on small vessel myographs. Urocortin inhibited U46619-induced contraction with reduction of the maximal response. Urocortin-induced relaxation was independent of the presence of endothelium. Inhibitors of nitric oxide (NO)-dependent dilator, NG-nitro-L-arginine methyl ester or 1H-[1,2,4]oxadizolo[4,3-a]quinoxalin-1-one, did not affect the relaxation. Astressin (100-500 nM), a corticotropin-releasing factor (CRF) receptor antagonist and KT5720, a protein kinase A (PKA) inhibitor reduced urocortin-induced relaxation. Urocortin produced less relaxant effect in 30 mM K+- than U46619-contracted arterial rings. Urocortin did not reduce CaCl2-induced contraction in 60 mM K+-containing solution. Ba2+ (100-500 microM) but not other K+ channel blockers reduced the relaxant responses to urocortin. Urocortin also relaxed the rings preconstricted by phorbol 12,13-diacetae in normal Krebs solution while this relaxation was less in a Ca2+-free solution. Our results show that urocortin relaxed rat pulmonary arteries via CRF receptor-mediated and PKA-dependent but endothelium/NO or voltage-gated Ca2+ channel-independent mechanisms. Stimulation of Ba2+-sensitive K+ channel may contribute to urocortin-induced relaxation. Finally, urocortin relaxed pulmonary arteries partly via inhibition of a PKC-dependent contractile mechanism.

Animals↗
PubMed2004

Melkerrson-Rosenthal syndrome with cardiac involvement.

Melkerrson-Rosenthal syndrome (MRS) is a granulomatous disease usually restricted to the orofacial region. We report a case of MRS in a 37-year-old Malay patient who presented with complete heart block on a background of recurrent oro-facial swelling and facial diplegia. Lip biopsy showed lymphohistocytic granulomatous inflammation typical for MRS. Extensive work-up excluded other causes of the complete heart block. To our knowledge, this is the first reported case of MRS affecting cardiac connective tissues and the first report of MRS in an ethnic Malay. We postulate granulomatous infiltration of the conductive tissues as the basis for the heart block. Another unusual feature of the case was the presence of left eye abduction limitation.

Adult↗
PubMed2004

Acute ophthalmoplegia with pupillary areflexia associated with anti-GQ1b antibody.

Raised anti-GQ1b antibody is associated with Miller Fisher syndrome, Guillain-Barre syndrome (GBS) with ophthalmoplegia, Bickerstaff's brain stem encephalitis, acute ophthalmoparesis without ataxia and ataxic GBS without opthalmoplegia. We report a rare case of acute ophthalmoplegia associated with anti-GQ1b antibody that also had pupillary areflexia. A 35-year-old Chinese lady presented with external ophthalmoplegia, pupillary areflexia and no other abnormalities of cranial nerves, muscle tone, deep tendon reflexes, limb power or cerebellar dysfunction. Anti-GQ1b IgG antibody titre was significantly elevated, while neuroimaging of brain and orbital structures, nerve conduction study and cerebral spinal fluid examination were normal. Pupillary areflexia should be recognized as another feature that may be present in conditions associated with raised anti-GQ1b antibody.

Acute Disease↗
PubMed2004

Abdominal complications from crack cocaine.

Not only is cocaine a powerfully addictive and dangerous drug of abuse, the use of the purified cocaine derivative crack has also reached epidemic proportions. Apart from causing fatal cardiorespiratory complications, crack cocaine is capable of producing surgical emergencies, which may or may not be associated with the pharmacology of cocaine itself. This is a report of crack-induced pneumoperitoneum, the mechanism of which seemed to be related to the prolonged Valsalva manoeuvre during crack smoking. Other differential diagnoses of crack related pneumoperitoneum are also discussed.

Adult↗
PubMed2004

Viral warts in children seen at a tertiary referral centre.

INTRODUCTION: This study aims to determine the epidemiology of viral warts in children seen at a tertiary referral centre and the treatments used. MATERIALS AND METHODS: This is a retrospective study of viral warts in children aged 12 years and below seen at the National Skin Centre in the year 2000. RESULTS: There were 302 cases of viral warts, 187 (61.9%) in boys and 115 (38.1%) in girls. The greatest number was seen at age 12 and none were noted in those below 1 year of age. The racial breakdown was as follows: 69.9% Chinese, 13.9% Malays, 11.3% Indians and 4.9% of other ethnic groups. Treatment with liquid nitrogen was used most commonly in 267 (88.4%) cases, with a clearance rate of 48.3%. Electrocautery was used in 11 cases with complete clearance in 8 cases. CONCLUSION: Viral warts are common in children, but uncommon in infants. There is no difference in distribution of warts among the races in Singapore. Liquid nitrogen and electrocautery are effective treatments of viral warts in children.

Age Distribution↗